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AE Zone AE

1% annual chance flood zone with base flood elevations determined

Where AE sits

Cross-section of a river floodplainDiagram: a river valley. The floodway is the channel and the land beside it; the 1%-annual-chance flood surface (the base flood elevation) covers the valley floor as zone A or AE; a narrow band higher up is shaded X, the 0.2% floodplain; higher ground is X.0.2% CHANCE A YEAR (500-YEAR)BASE FLOOD ELEVATION · 1% A YEARXAEFloodwayAEX
  1. A / AE Inside the 1%-a-year floodplain: about a 26% chance of flooding over a 30-year mortgage. AE has a mapped base flood elevation; plain A does not.
  2. Floodway The channel and the land beside it that has to be kept clear enough to carry the flood. Building here is tightly limited.
  3. X shaded The 0.2% (500-year) floodplain, plus some levee-protected and very shallow flood areas.
  4. X Outside both lines. No federal requirement to insure, which is not the same as no risk.

What Is Zone AE?

Zone AE is the most common high-risk flood zone designation. FEMA classifies these areas as having a 1% annual chance of flooding (the "100-year floodplain"), which translates to a 26% chance of flooding over a 30-year mortgage. However, many flood experts note that climate change is increasing flood frequency faster than FEMA maps are updated, so actual risk in many AE zones now exceeds the 1% threshold.

FEMA determines Base Flood Elevations (BFEs) for Zone AE areas, which indicate the height floodwaters are expected to reach during a flood with a 1% chance of happening in any year. These BFEs set the minimum elevation that new and substantially improved buildings must meet (many communities require more), and they are the benchmark for Letters of Map Amendment.

Zone AE replaced the older numbered A zones (A1-A30) on newer flood maps. If your property was previously in an A-numbered zone, it is now likely classified as AE.

Flood Insurance Requirements

Flood insurance is required if you have a mortgage from a federally regulated or insured lender, or a federally backed loan such as FHA, VA, Fannie Mae or Freddie Mac. This is a Special Flood Hazard Area (SFHA).

How the National Flood Insurance Program works →

Base Flood Elevation (BFE)

Yes — Base Flood Elevations are determined in Zone AE. Since Risk Rating 2.0, NFIP premiums are rated on the building's own flood risk, including its first-floor height, rather than on the flood zone.

What base flood elevation means and how to read it →

Check Your Property's Flood Zone

Enter your address to see if your property is in Zone AE